Process for producing titanium group metals



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Oct. 20, 1959 R. s. DEAN E AL 2,909,473

PROCESS FOR PRODUCING TITANIUM GROUP METALS Filed-Sept. 4, 1956 n m A Clm Zsowu; E x AVG. VALENCE Na in mi. H; svoLveo/emm 1 @zMdJ'dun 20.21%INVENTORS'.

United States Patent PROCESS FOR PRODUCING TITANIUM GROUP METALS 2Claims. (Cl. 20464) This invention relates to the production of puretitanium group metals from their oxidic compounds such as natural.oxides or intermediate products made in refining ores of these metals.It relates in particular to the production from such oxidic compounds ofa titanium group metal alloy in suitable form for an electrolytic stepso contrived that pure titanium is produced together with productsnecessary to the step of producing titanium group metal alloy from theoxidic material.

Our invention consists of the following preferred sequential steps:

1) Reduction of the titanium group metal from its oxidic compound to aselected alloy of titanium group metal from which titanium group metalonly will be dissolved by the subsequent step of anodic solution in afused chloride cell bath, for example, an alloy of ironcopper, andtitanium produced by magnesium reduction or an alloy ofaluminum-iron-silicon and titanium produced by aluminum reduction.

(2) Separation of the titanium group alloy from the other reactionproducts, for example, acid solution of magnesium oxide and excessmagnesium.

(3) Forming an anode of the titanium group metal alloy, e.g., casting,comminuting and holding it on suitable support.

(4) Selection of a fused cell bath which will dissolve titanium alonefrom the alloy such as a fused salt bath having a composition in thethree component system NaTiCl having about 4.5-6.0% soluble titaniumhaving an average valence of titanium to ferric sulphate of 2.1-2.5 andenough free sodium per gram of'salt to evolve 5-4.0 ml. H in acidifiedferric sulphate.

, (5) Selection of a cathode inert to the fused bath, when acting as acathode, and placed in suitable space relationship to the comminutedanode material supported on a support inert to the fused bath whenconnected as an anode. i

(6) Selection of a current having suitable polarity and amperage todissolve the titanium only at the anode and form coarsely crystallinetitanium at the cathode. Such as a direct current for alloys other thanthose of alumi num providing from 100-2000 amperes/sq. ft. on theoriginal cathode. A direct current providing from 100 2000 amperes/sq.ft. on the original cathode with a superimposed alternating current of60 cycles and amperage about that of the direct current for aluminum(10) Separating the anode residue from thefused cell bath.

7 (ll) Separating material in anode residue, such as copper, torecirculate to the first step. V f The production'of titanium groupmetal alloy accord- 2,909,173 Patented Oct. 20, 1959 2 oxidic titaniumcompound in the presence of an alloying metal or its reducible oxide.This alloying element may be present in the oxidic titanium compound,for example, iron or it may be added to the reduction reaction, e.g.copper. It is essential to my invention that the alloying elements bemore noble than titanium in the electrolyte used for refining, since inthe step of electrolytic refining the alloying elements must berecovered in the anode residue. A preferred reducing step for use in myinvention consists in dispersing the oxidic compound of the element tobe reduced in a molten metal having an oxide of greater negative freeenergy than the lowest oxide of the metal to be reduced. .For example,titanium dioxide is dispersed in molten magnesium or alumina. Thisdispersion takes place with partial reduction. The dispersion is thenheated to a temperature and for a time to bring about substantiallycomplete reduction of the metal of the titanium group and the alloyingelements present in the oxidic material, e.g., iron and chromium. Whenmagnesium is .used as the reducing agent I prefer to add copper to it sothat the titanium group metal alloy a of reaction and-from the vessel inwhich the reaction formed will contain about 10% copper. The presence ofthis copper lowers the melting and softening point of the alloy so thatit is agglomerated to larger particles and is hence more readilyseparated. from the other products takes place.

The reduction step produces the alloy of the titanium group metal inadmixture with oxide of the reducing metal and any excess of reducingmetal.

The next step is the separation of titanium group metal alloy from theoxide of the reducing metal and any excess reducing metal. This may beaccomplished in a number of ways. For example, the titanium alloymay beagglomerated by heating with a flux for the oxide formed inthe reactionor when the reducing metal is magnesium, both magnesium and magnesiumoxide can be dissolved from the titanium group metal alloy by diluteacid. To prevent solutionof the titanium group metal, air must beexcluded from the operation. When, for example, the reducing metal isaluminum and the alloying metal iron, an excess of aluminum may be usedwhich maybe present without causing difliculty in the electrolytic stepfalls linearly from 10% at verylow oxygen to substantially none at 5%oxygen.

By use of special procedures such as superposed alternating current,alloys with combinations of higher aluminum and/or silicon and oxygencontents may be refined. Not all titanium group alloysmay be refinedwith equal facility. We prefer to use .alloys containing not more than10% of the followingelements when present singly: Fe, O, N, Cr, Al, V.We have found, however,

ing to our invention is accomplished byfreducing-an that when aluminumand/ or silicon are present, the oxygen content must be kept to a lowerfigure to prevent difficulties in uniform and effective solution of thetita-' nium from the anode. a p u The anode from the alloys to berefined by ourproc ess is preferably made up of comminuted materialwhich is retained on a suitable support. The refining of such comminutedmaterial is described in detail in R. ,S. Deans co-pending applicationSerial No.. 470,610,; filed November 23, 1954, now Patent No. 2.7834361.E135.

invention must be selected with regard to the elements contained in thealloys and the nature of the pure titanium it is desired to produce.

In a preferred form of our invention we use the alloy in comminuted formas an anode and an electrolyte and procedure disclosed in Deansapplication Serial No. 600,039, filed July 25, 1956. The preferredelectrolyte in this form of our invention is a single phase compositionselected from the system Ti-NaCl which is defined by having a totalsoluble titanium content of 16%, an average valence as determined byreduction of acidified ferric sulphate of 2.052.5 and a sodium contentas determined by gas evolution in acidified ferric sulphatecorresponding to a hydrogen evolution of .1-6 ml. per gram ofelectrolyte.

In another form of our invention we use an electrolyte consistingessentially of 97% NaCl, 3% TiCl and provide means for maintaining ahigher titanium valence at the cathode than at the anode. Such means mayhe the addition of TiCL; or C1 in the cathode area or the use of anauxiliary circuit having a graphite anode so disposed as to increase thevalence of titanium at the cathode.

In either of these embodiments of our invention the titanium dissolvesat the anode as chloride and diffuses into cathode zone where it isreduced by a solution of sodium formed at the cathode and diffusing intothe bath. In this way the titanium is formed adherent the cathode in amass having the structure described in the co-pending application of W.W. Gullett, Serial No. 592,543, filed June 20, 1956, now Patent No.2,874,454.

The anode residue from the anodic solution of the titanium group alloycontains all the alloying ingredients including oxygen, nitrogen,carbon, iron, chromium, manganese, vanadium, copper and others.

It is desirable to treat this residue for the recovery of ingredientsused in the initial reducing operation such as copper. This treatmentmay be by hydrometallurgical or pyrometallurgical processes. In certaininstances, acid leaching will leave a residue of copper and titaniumdioxide which may be returned to the reducing step; in other instances afire refining step may be used to recover substantially pure copper forreuse.

The titanium group metal of our invention is recovered as bundles ofcoarse filamentary particles having their interstices filled with salt,preferably adhering to the cathode. The bundles of particles are brokenup and leached with very dilute acid providing as the final product ofour invention pure titanium group metal.

Refining in the practice of our invention takes place essentially at theanode. The concentration of sodium in the electrolyte must be such thatany chlorides formed from the metallic elements alloyed with thetitanium will be reduced to metal and thus not enter the electrolyte.This reduction may be regarded as a reaction with titanium, but it is nodoubt an indirect one in which titanium dissolves to increase the sodiumcontent around the anode material and the sodium in turn reduces anydissolved chlorides.

Published data on metallic chloride decomposition voltages, for example,J. Electrochem Soc. 103, 1956, p. 8, gives a value of about 3.3 volts at800 C. for sodium and 1.8, 1.6, 1.5 for Mn, V and Cr respectively.Aluminum is not given in this compilation, but from published freeenergy data would be about 1.5 volts for AlCl and somewhat higherperhaps 1.8 for AlCl.

The reducing power of the cell bath containing sodium is bestillustrated by consideration of the ternary diagram of three parametersas shown in Deans co-pending application Serial No. 600,039, filed July25, 1956. These parameters are:

(1) Percent soluble titanium (2) Chlorine as percent soluble titaniumaverage valence (3) Sodium as hydrogen evolved per gram in acidifiedferric sulphate The determination of these parameters and their use tocontrol the process of producing titanium is disclosed in- Deansco-pending application with R. Resnick, Serial No. 605,231, filed August20, 1956.

The lines of equal reducing power for metallic chlorides are roughlyparallel to the line xy in the ternary diagram of Deans application.

In Figure 1 we have reproduced the ternary diagram from Deansapplication and have shown the approximate position of the several linesin terms of metallic chloride decomposition voltages. These lines meanthat any metallic chloride having a decomposition voltage below thatshown on a given line will not be dissolved in the presence of activemetallic titanium in a cell bath having a composition to the right ofthe line.

The provision of active metallic titanium in the anode material is animportant part of our process. It is provided directly in many of thealloys to be refined, but in other alloys particularly those ofaluminum, the residue of the alloy after the anodic solution of some ofthe titanium may become passive due to film formation. With such alloyscomminuted crude titanium may be conveniently added to the anodematerial or an alternating current may be superposed on the directcurrent in the cell. This maintains the anode material in an activestate.

It will be observed that the high titanium and sodium concentrationrequired in the cell bath for refining from such elements as aluminumand manganese does not precipitate titanium because of the tendency ofsuch solutions to supersaturate as set forth in Deans application,Serial No. 600,039, filed July 25, 1956.

As set forth in our co-pending application, Serial No. 601,705, filedAugust 2, 1956, large pure titanium crystals are formed by thedifiustion of sodium from the cathode into the electrolyte justdescribed with the formation of a supersaturated solution andcrystallization therefrom of titanium.

The titanium content of the electrolyte in the cathode zone ismaintained by solution of titanium from the anode material. The surfaceof the anode material and its space relationship to the cathode must besuch as to maintain the electrolyte concentration.

EXAMPLE I In this example we take lbs. of finely ground rutile and mixit into 50 lbs. of magnesium containing 5 lbs. of copper. To accomplishthe dispersion of our invention, we use a rod mill heated to 750 C. andcarefully sealed from the inclusion of air. After the initial mixing weheat the rod mill to 900 C. for 1 hour while rotating.

We then cool the contents of the mill in argon and remove the reactionmixture. We treat this reaction mixture with 5% sulphuric acid in theabsence of air. The insoluble residue is washed with air free water andvacuum dried. The product analyses 87% Ti, 10% copper, balance oxygenand incidental impurities. We melt this product in a graphite cruciblein an induction furnace provided with an argon atmosphere, we skim otfinsoluble impurities, and cast it into bars 2" diameter by 12" long. Wemake these bars an anode in an electrolytic cell having an electrolyteof sodium chloride to which has been added soluble titanium chloride inan amount equal to 3% Ti. The average valence of the titanium in thechloride is 2.5, and the sodium content corresponding to 0.8 ml. of Hper gram. The cell is provided with an inert atmosphere, an inertcathode concentric with the anode, and an auxiliary circuit consistingof a foraminous cathode surrounding the anode and a graphite anoderelatively near the cathode. The current in the main refining circuit is500 amperes/ sq. ft. on the cathode and 2000 amperes/sq. ft. on theanode. The current in the auxiliary circuit is so adjusted that the opencircuit voltage of the cell between main anode and cathode is in thereverse direction to the applied voltage. The anode goes into solutionsmoothly and particulate titanium is deposited at the cathode in bundlesof crystals having their interstices filled with salt. The anode residuefalls to the bottom of the cell from which it is recovered. We leach theanode residue with water to remove salt and fuse the leached residue ina graphite crucible with a little charcoal. We skim off the impuritiesand cast the copper in pigs for returning to the reducing step. Weremove the titanium from the cathode and leach with dilute hydrochloricacid to obtain a particulate titanium of high purity.

EXAMPLE II In this example we take 105 lbs. of Sorel slag having thefollowing analysis and mesh size:

Equiv. .2 CI'203.20 Fe-6.4 V205-.5 3 SiO -SZ MnO-.22 Aho -65 C.06 (ho-1.4 S.21 MgO'4.5

, 88% through 200 mesh We mix this with 50 lbs. of magnesium and in aheated rod mill as described in Example I. After reaction the product iscooled in argon and removed from the mill. We leach this with 5%sulphuric acid in the absence of air and vacuum dry the residue. Thisresidue analyses 85% Ti, 9% Fe, 6% oxygen and incidental impurities.

We melt and cast this alloy into bars which are broken up to fragmentsabout /2" average diameter. These fragments are placed on the bottom ofan iron pot which also serves as the anode of an electrolytic cell andis provided with an inert atmosphere and an electrolyte of 90% NaCl, 10%TiCl An iron rod is disposed centrally in the pot to serve as cathode,and a DC. current corresponding to 2500 amps/sq. ft. on the rod ispassed through the cell. The alloyed iron and the incidental impuritiesremain as anode residue on the bottom of the pot while the titaniumdissolves as dichloride and particulate titanium is formed adhering tothe cathode from which it is recovered by leaching with dilutehydrochloric acid. The anode residue is recovered from the bottom of thecell and is subjected to magnetic separation to remove the iron andleave a non-magnetic fraction essentially TiO which is returned to thereducing step.

EXAMPLE III In this example we use aluminum as the reducing material forthe titanium oxide in Sorel slag. We use a substantial excess over thealuminum required to reduce thetitanium and iron oxides of the slag.

. 'In this example we use 100 grams slag having the analyses shown inExample II, and 150 grams aluminum.

We heat this mixture in an argon atmosphere with stirring to 1000? C.and allow the reaction mass to separate into a metallic layer and anon-metallic layer. The metallic layer contains 36% Ti, 4% Fe, 60% Al,and only small amounts of impurities. We now take this metallic layerand break it up into fragments. We heat these fragments with an excessof molten zinc in an argon atmosphere until the aluminum is dissolvedleaving as a residue a titanium-iron alloy. This residue is recovered byfiltration on .a Pasalt filter, and is made into anodes and refined inaccordance with the previous examples. The zinc-aluminum alloy isdistilled for the recovery of the two metals.

EXAMPLE IV In this example we proceed as in Example I to produce analloyof essentially. titanium and copper. We melt this alloy in afgnaphitecrucible lined with lime which prevents the absorption of carbon intothe alloy. We add 1% to the molten alloy in order to flux and removecertain impurities especially silicon. The molten titanium'copper alloyis bottom poured into a graphite 75 6 mold to separate it from thefluxed impurities which float. All of the operations of this example arecarried out in an argon atmosphere.

The cast purified copper-titanium alloy can now be welded to other barsof the alloy to provide a continuous anode for electro-refiningaccording to Example I. In this example, however, we provide aforaminous neutral member about A" in front of the cathode on which thebundles of titanium particles are formed. This prevents thecontamination of the deposit by sealing of the cathode caused byalloying of sodium with the metal of the cathode.

EXAMPLE V In this example we make anode material from Sorel slag as inExample II. We add copper, however, to the reaction mixture in the hotrod mill so'that we obtain a product containing 78% Ti, 10% Cu, 9% Fe,and 3% oxygen. We melt this in a graphite crucible in an inductionfurnace with an argon atmosphere and then after cooling eomminute themass to pass a 4 mesh screen. The comminuted material was placed in aniron basket annularly disposed around an iron rod cathode in acylindrical cell like that disclosed in our co-pending application,Serial No. 601,705, filed August 2, 1956. The log of this examplefollows:

Current during operation Time from Start Amperes Ampere Hours 1 hour 2020 2hnm's 30 30 3 hours 40 40 4ho 50 50 5hnmq 50 5O Ghours 60 60 7hours70 Sho 80 80 Qhnnrs- 80 80 9% hours 80 40 Ano de specificationsComposition- O 3.0% O-.40% Fe-- 9.0%

N .021% Cu--l0.2% Balance Ti Character-fragments Weight -10 lbs.Immersed area-3.0 sq. ft. Current density (ave.)--1.82 amps/sq. ft.

Location-In perforated steel container dispersed annularly 3 inches fromcathode Cathode specifications:

,Compositionmild steel Size--%" diameter rod Immersed area-18.85 sq. in.a Current density-407 amperes/ sq. in. Cell bath:

NaCl plus 5.05% soluble Ti Average valence of Ti to ferric sulphate-2.2

Hydrogen evolution in ferric sulphate--2.4 ml./ gram Temperature ofoperation: 850 C. Deposit:

Plate-.003 inch thick Salt layer- 015 inch thick Crystals1.0 inch thickTotal weight of deposit-480 grams Weight of large crystals420 gramsWeightof salt-50 grams Weight of fine crystals-8 grams Density largecrystal deposit-2.2

7 Analysis:

Plate-98% Ti, 2% Na Fine crystals99.8% Ti Large crystals-99.99% TiBrinell hardness large crystals melted in argon 65 EXAMPLE VI In thisexample we make an anode material from rutile by adding it to slightlymore than its stoichiometric equivalent of aluminum held at 1500 C. inan electric furnace. Reaction is rapid, and the final product is analloy of 90% titanium, 8% aluminum, and 2% impurities mostly silicon andiron. In order to dissolve titanium alone from this anode material it isnecessary to overcome the passivity of the titanium. In this example weaccomplish this by mixing with the comminuted alloy 20% of comminutedcommercially pure titanium, which reacts with the cell bath toprecipitate the impurities which would otherwise enter the bath/ Theoperation in this example is carried on in accordance with that ofExample V except as follows:

Cell bath:

NaCl plus 6.5% soluble Ti Average valence of Ti to ferric sulphate-2.1Hydrogen evolution in ferric sulphate4.0 ml./ gram The product obtainedis of the same purity and crystal structure and distribution as inExample V.

EXAMPLE VII In this example we proceed exactly as in Example VI exceptthat we do not mix comminuted commercially pure titanium with thecomminuted alloy. We superpose a 60 cycle alternating current of thesame current density on the direct current passed through the cell. Theoperation and results are identical with those in Example VI.

EXAMPLE VIII In the co-pending application of Dean, Serial No. 592,-089, filed June 18, 1956, it is disclosed that zirconium formscompositions in the system ZrNa-Cl which are analogous to the titaniumcomposition used as the cell bath in Example V. I have found that a cellbath having the following description may be used: Sodium chloride plus6.02% Zr, average valence of Zr to ferric sulphate 3.4. Hydrogenevolution in ferric sulphate 2.4 ml./ gram. I proceed with the use ofthis cell bath as in Example V, except that the anode has the followingcomposition and is made by reducing ZrO with magnesium in the hot rodmill of Example I, dissolving the MgO from the reduced zirconium,sintering the zirconium at 1000 C. in argon and comminuting to fragmentsinch average diameter. The deposit is of the same character as that ofExample V and the analysis of the large crystals is 99.99% Zr. Brinellhardness of melted button 71.

EXAMPLE IX In this example I prepare a manganese-aluminum-titanium alloyby the reaction of aluminum, manganese dioxide and titanium dioxide. Theproportions are so taken that the resulting alloy contains 85% Ti, 10%Mn, Al. The alloy is prepared by heating the mixture in an electricfurnace with a flux consisting of 90% CaF cryolite. We electrorefinethis alloy at a temperature below the eutectoid that is in the rangewhere only alpha titanium and the compound TiMn are present. This isnecessary to obtain good refining. Manganese is more noble than titaniumin fused alkalinous chlorides containing titanium chlorides and sodiumin the composition ranges disclosed in Deans co-pending application,Serial No. 592,089, filed June 18, 1956. However, the manganese metalwhich is precipitated by titanium dissolves in it at temperatures wherebeta solid solution is formed. To effectively refine from manganese itis therefore'necessary to work at temperatures where no beta solidsolution of titanium and manganese is stable. For the alloy of thisexample we have found this to be 600 C. :We therefore use an electrolytewhich is molten at this temperature. The basis of this'electrolyte is30% NaCl, 70% CaCl To this electrolyte, after deoxidation in the moltencondition by adding TiO and Ti, we add the reduction mixture of 'I iCland sodium disclosed in William W. Gulletts co-pending application. Thisreduction mixture contains 20% Ti as soluble Ti. 25% by weight of thismixture is added to the fused NaCl+CaCl The resulting bath contains 5%soluble Ti, average valence 2.4, hydrogen evolution in ferric sulphate2.8 ml./ gram.

I place the comminuted manganese-titanium-aluminum alloy in an ironanode basket and refine in accordance with Example V. I obtain on thecathode pure titanium which when melted in argon has a Brinell hardnessof 70.

EXAMPLE X In this example we take 240 lbs. of Sorel slag of thecomposition given in Example II. We mix this with 55 lbs. of granulatedAl and compact into pellets. We place these pellets together with 10lbs. CaF and 1 lb. cryolite in a closed graphite crucible and heat to1750 C. There is formed a regulus which analyzes:

Insol. mostly Al O 6% And a slag containing most of the A1 0 formed inthe reaction This regulus is comminuted to form an anode product whichis refined in accordance with the procedure of Example V, except thatthe direct current is periodically reversed for one (1) second out ofevery five (5). The titanium in the anode product is completelydissolved and the cathode deposit is identical with that of Example V.

EXAMPLE XI We proceed as in Example V, except that the electrolyte is65% SrCl and 35% NaCl in place of the NaCl in Example V. The controlparameters of soluble titanium, average valence, and hydrogen evolutionare substantially the same as in Example V. The temperature of operationis 750 C. The log of operation and the results are substantially thesame except that the plate formed contains Sr in place of Na.

What is claimed is:

1. Process of producing a substantially oxygen-free titanium group metalof high purity from an impure oxidic compound of the titanium groupmetal containing a substantial amount of iron, which comprises reactingthe impure oxidic compound With magnesium, at a temperature above themelting point of magnesium, out of access to air, under conditions toproduce a frangible crude alloy consisting essentially of from 5 to 10%by weight of iron, 3 to 5% by weight of interstitial oxygen and thebalance titanium group metal, separating said crude alloy fromassociated reaction products, comminuting the frangible crude alloy, andelectrorefining the comminuted alloy by making the same an anode in anelectrolytic cell provided with a cathode and containing a cell bathconsisting essentially of molten sodium chloride containing dissolvedtherein from 3 to 7% of titanium group metal, as chlo ride, having avalence of 2.0-2.6 and 0.l-3.0% dissolved metallic sodium andelectrolyzing at a cathode current density of 400-2500 amperes persquare foot to produce coarse crystals of pure titanium group metaladherent to the cathode.

2. Process of producing substantially oxygen-freetitanium of high purityfrom Sorel slag which comprises reacting the Sorel slag with magnesium,in the app oximate ratio of 5 parts by weight of magnesium to an amountof the Screl slag corresponding to 8 parts by weight of TiO out ofaccess to air and at a temperature above the melting point of magnesium,whereby to produce a frangible crude alloy consisting essentially offrom 5 to 10% by weight of iron, 3 to 5% by weight of interstitialoxygen and titanium the remainder, comminuting the frangible crudealloy, and electrorefining the comrninuted alloy by making the same ananode in an electrolytic cell provided with a cathode and containing acell bath consisting essentially of molten sodium chloride containingdissolved therein from 3 to 7% of titanium group metal, as chloride,having a valence of 2.0-2.6 and (ll-3.0% dissolved metallic sodium andelectrolyzing at a cathode current density of 4002500 amperes per squarefoot to produce coarse crystals of pure titanium adherent to thecathode.

5 References Cited in the file of this patent UNITED STATES PATENTS1,534,709 Holt Apr. 21, 1925 2,734,856 Schultz et a1. Feb. 14, 19562,757,135 Gleave et al July 31, 1956 10 2,817,631 Gullett Dec. 24, 1957UNITED STATES PATENT O.F.F ICE CERTIFICATE OF CORRECTION Patent "No,2,909,473 Q October 20, 1959 Reginald vSc. Dean et al0 It isherebycertifie'd that error appears in the printed specification of theabove numbered patent requiring correction and that the said LettersPatent should read as corrected below.

Column 2, line '72, strike out now Patent Noo 2 78x8610" and insertinstead a period after "November 23, 1954;"a

Signed and sealed this 10th day of May 1%0a Attest:

H. ,AXLINE ROBERT C WATSON

1. PROCESS OF PRODUCING A SUBSTANTIALLY OXYGEN-FREE TITANIUM GROUP METALOF HIGH PURITY FROM AN IMPURE OXIDIC COMPOUND OF THE TITANIUM GROUPMETAL CONTAINING A SUBSTANTIAL AMOUNT OF IRON, WHICH COMPRISES REACTINGTHE IMPURE OXIDIC COMPOUND WITH MAGNESIUM, AT A TEMPERATURE TURE ABOVETHE MELTING POINT OF MAGNEWIUM, OUT OF ACCESS TO AIR, UNDER CONDITIONSTO PRODUCE A FRANGIBLE CRUDE ALLOY CONSISTING ESSENTIALLY OF FROM 5 TO10% BY WEIGHT OF IRON 3 TO 5% BY WEIGHT OF INTERSTITIAL OXYGEN AND THEBALANCE TITANIUM GROUP METAL, SEPARATING SAID CRUDE ALLOY FROMASSOCIATED REACTION PRODUCTS, COMMINUTING THE FRANGIBLE CRUDE ALLOY, ANDELECTROEFINING THE COMMINUTED ALLOY BY MAKING THE SAME AN ANODE IN ANELECTROLYTIC CELL PROVIDED WITH A CATHODE AND CONTAINING A CELL BATHCONSISTING ESSENTIALLY OF MOLTEN SODIUM CHLORIDE CONTAINING DISSOLVEDTHEREIN FROM 3 TO 7% OF TITANIUM GROUP METAL, AS CHLORIDE, HAVING AVALENCE OF 2.0-2.6 AND 0.1-3.0% DISSOLVED METALLIC SODIUM ANDELECTROLYZING AT A CATHODE CURRENT DENSITY OF 400-2500 AMPERES PERSQUARE FOOT TO PRODUCE COARSE CRYSTALS OF PURE TITANIUM GROUP METALADHERENT THE CATHODE.